Tempest Wolves (
When Rimuru gave Ranga a name, it triggered a piece of Demon Essence. Unlike his father, Ranga believes in the concept of "All for One." As a result, his fellow wolves also evolved into Tempest Wolves.
Direwolves are not really supposed to evolve toward the "storm" element in the first place—that was just a side effect of the name Rimuru gave out.
Tempest Wolves have jet black fur, which gives a feeling of bewitching gloss and a glossy finish. The storm element gave the wolf pack an ever-so-slight purplish shine to their black color.
They are fast and don't show any fatigue. They can run for 3 hours at 80 km/h without taking a break.
- Light Novel Volume 1